Github user JamesRTaylor commented on a diff in the pull request:
https://github.com/apache/phoenix/pull/34#discussion_r23278372
--- Diff:
phoenix-core/src/main/java/org/apache/phoenix/compile/IndexColumnExpressionCompiler.java
---
@@ -0,0 +1,311 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE
+ * file distributed with this work for additional information regarding
copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the "License"); you may
not use this file except in compliance with the
+ * License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0 Unless required by
+ * applicable law or agreed to in writing, software distributed under the
License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
implied. See the License for the specific language
+ * governing permissions and limitations under the License.
+ */
+package org.apache.phoenix.compile;
+
+import java.sql.SQLException;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+
+import org.apache.hadoop.hbase.client.Scan;
+import org.apache.phoenix.compile.GroupByCompiler.GroupBy;
+import org.apache.phoenix.expression.ColumnExpression;
+import org.apache.phoenix.expression.Expression;
+import org.apache.phoenix.parse.AddParseNode;
+import org.apache.phoenix.parse.AndParseNode;
+import org.apache.phoenix.parse.ArrayAllComparisonNode;
+import org.apache.phoenix.parse.ArrayAnyComparisonNode;
+import org.apache.phoenix.parse.ArrayElemRefNode;
+import org.apache.phoenix.parse.CaseParseNode;
+import org.apache.phoenix.parse.CastParseNode;
+import org.apache.phoenix.parse.ColumnDef;
+import org.apache.phoenix.parse.ColumnParseNode;
+import org.apache.phoenix.parse.ComparisonParseNode;
+import org.apache.phoenix.parse.DivideParseNode;
+import org.apache.phoenix.parse.FunctionParseNode;
+import org.apache.phoenix.parse.ModulusParseNode;
+import org.apache.phoenix.parse.MultiplyParseNode;
+import org.apache.phoenix.parse.NamedTableNode;
+import org.apache.phoenix.parse.NotParseNode;
+import org.apache.phoenix.parse.OrParseNode;
+import org.apache.phoenix.parse.ParseNode;
+import org.apache.phoenix.parse.ParseNodeFactory;
+import org.apache.phoenix.parse.RowValueConstructorParseNode;
+import org.apache.phoenix.parse.SQLParser;
+import org.apache.phoenix.parse.StringConcatParseNode;
+import org.apache.phoenix.parse.SubtractParseNode;
+import org.apache.phoenix.parse.TableName;
+import org.apache.phoenix.schema.PColumn;
+import org.apache.phoenix.schema.PTable;
+import org.apache.phoenix.schema.PTableType;
+import org.apache.phoenix.schema.types.PDataType;
+import org.apache.phoenix.util.IndexUtil;
+
+import com.google.common.collect.Maps;
+
+/**
+ * Visitor that checks if nodes other than ColumnParseNode are present as
an expression in an index. If the expression
+ * is present, then the node is not visited but processed as a
ColumnParseNode.
+ */
+public class IndexColumnExpressionCompiler extends ExpressionCompiler {
+
+ private static final ParseNodeFactory FACTORY = new ParseNodeFactory();
+ private final Map<String, Expression> expressionMap;
+
+ IndexColumnExpressionCompiler(StatementContext context) {
+ this(context, GroupBy.EMPTY_GROUP_BY, false);
+ }
+
+ IndexColumnExpressionCompiler(StatementContext context, boolean
resolveViewConstants) {
+ this(context, GroupBy.EMPTY_GROUP_BY, resolveViewConstants);
+ }
+
+ IndexColumnExpressionCompiler(StatementContext context, GroupBy
groupBy) {
+ this(context, groupBy, false);
+ }
+
+ IndexColumnExpressionCompiler(StatementContext context, GroupBy
groupBy, boolean resolveViewConstants) {
+ super(context, groupBy, resolveViewConstants);
+ expressionMap =
Maps.newHashMapWithExpectedSize(context.getCurrentTable().getTable().getColumns().size());
+ for (PColumn column :
context.getCurrentTable().getTable().getColumns()) {
--- End diff --
I meant to create a map from <Functional Expression> -> <Index Column
Expression> where you use this to look for occurrences of the functional
expression to replace with a reference to the column expression in the index
table. You'd do a get into the map from the
ExpressionCompiler.wrapGroupByExpression() which is called on each visitLeave
method. If you find an entry, you use the ColumnExpression into the index
table, otherwise, you use the original expression. This is the expression you
provide as an argument to super.wrapGroupByExpression(). Let's talk in person
tomorrow if this doesn't make sense.
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